package com.ksyun.seckill.keygen;


import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;


/**
 * 全局id生成器
 */
@Component
public class RedisIdWorker {


    /*
    *
    * 开始的时间戳
    * */
    private static final long BEGIN_TIMESTAMP = 1640995200L;

    /*
    * 序列号的位数
    *
    * */
    private static final int COUNT_BITS=32;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    public static void main(String[] args) {
        LocalDateTime time=LocalDateTime.of(2022,1,1,0,0,0);
        long second = time.toEpochSecond(ZoneOffset.UTC);
        System.out.println("second="+second);
    }

    public long nextId(String keyPrefix){
        //1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timeStamp = nowSecond - BEGIN_TIMESTAMP;

        //2.生成序列号
        //2.1获取当前日期，精确到天
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        //2.2 自增长
        long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);

        //3.拼接并返回
        //或运算即可填充
        return timeStamp<<COUNT_BITS | count;
    }
}
